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Alpiq to showcase extended hydropower capabilities during Z'Mutt visit

As part of the XFLEX HYDRO project, Swiss power group Alpiq will demonstrate its reversible pump-turbine technology to international partners. The private visit at Z'Mutt pumping station will underline critical technological strategies to increase the flexibility and reliability of the European electricity grid.

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LAUSANNE, June 16, 2023 - Alpiq, a leading Swiss energy services provider and electricity producer, will host a private visit to the Z’Mutt hydropower plant for the partners of the European research and innovation project XFLEX HYDRO on 23 June 2023.

The purpose of the visit is to showcase a new reversible pump-turbine in operation and highlight a set of enabling innovations used during the modernisation of the station. The implementation of this technology is part of a Europe-wide examination of inventive solutions designed to improve the adaptability of hydropower plants and safeguard the European electricity grid against potential disruptions caused by the integration of intermittent renewable energy.

The upgrade of the Z’Mutt pumping station, a part of Grande Dixence SA, the country’s most powerful hydroelectric complex, was not without its challenges. The project faced disruptions due to the pandemic and geopolitical tensions that rippled through the global supply chain.

"Upgrading material in an old power plant is always tricky, and external factors have made this project more challenging than expected. Luckily, as this modernisation project took place as part of the XFLEX HYDRO project, we were able to call upon international partners to overcome implementation challenges," explained Nicolas Hugo, electromechanical engineer and XFLEX HYDRO project manager.

The implementation was also expedited by the Alpiq team's innovative use of a numerical clone of the power plant, which was instrumental in solving issues and fast-tracking the installation of new equipment.

A key feature of the upgrade is the installation of a new 5 MW variable speed reversible pump-turbine to replace one of the plant's existing units. When installed with modern power electronics and smart controls, it will demonstrate a high range of flexibility. This enhancement not only modernises the station but also provides a crucial step in future-proofing the European electricity grid against potential disruptions.

This visit will offer European experts an opportunity to experience first-hand the operation of the reversible pump-turbine technology. Recent measurements carried out on the instrumented runner and pump-turbine have validated the methods used to predict the lifetime of components and confirmed that operations under high-flexibility conditions remain safe over the long term.

Bernard Valluy, Head of Group Operations at Alpiq, stated: "The expertise we've gained through the XFLEX HYDRO project is of course invaluable for Alpiq, but operating the two main variable speed technology and ternary units will also enable us to provide advice to international project managers who may be interested in flexibility upgrades."

The international XFLEX HYDRO consortium is a partner of the visit to Z’Mutt pumping station, one of six sites chosen to study the use of new technologies to improve power grid stability and renewable energy integration in Europe. Z'Mutt, commissioned in 1964 and located at the foot of the Matterhorn, boasts a total pumping capacity of 88 MW across five existing pumps.